Material for plastic lens, production process of the material, composition for plastic lens, plastic lens obtained by curing the composition, and production process of the plastic lens

ABSTRACT

A material for plastic lenses, comprising at least one group represented by the following formula (1) as a terminal group and a group represented by the following formula (2) as a repeating unit.  
                 
 
     wherein each R 1  independently represents an allyl group or a methallyl group, A 1  and A 2  each independently represents an organic residue derived from a dicarboxylic acid or a carboxylic anhydride, and each X independently represents an organic residue derived from a polyhydric alcohol having from 2 to 3 hydroxyl groups and containing an alicyclic structure within the molecule, provided that by the ester bonding, X can have a branched structure having a group of formula (1) as a terminal group and a group of formula (2) as a repeating unit.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is an application filed under 35 U.S.C. §111(a)claiming benefit pursuant to 35 U.S.C. §119(e)(1) of the filing date ofthe Provisional Application 60/218,802 filed Jul. 18, 2000, pursuant to35 §111(b).

TECHNICAL FIELD

[0002] The present invention relates to a material for plastic lenses, aproduction process of the material, a plastic lens compositioncontaining the material, a plastic lens obtained by curing thecomposition, and a production process of the plastic lens.

[0003] More specifically, the present invention relates to a plasticlens material which can be used for a plastic lens composition capableof preventing damage to a lens or a mold due to curing shrinkage arisingas a problem during the polymerization of a polyethylene glycolpoly(allyl carbonate)-based plastic lens material; a production processof the material; a plastic lens composition containing the material; aplastic lens obtained by curing the composition; and a productionprocess of the plastic lens.

BACKGROUND ART

[0004] In recent years, organic glasses are widely used as opticalmaterials in camera, television, prism, telescope and ophthalmic lenses.In particular, in the field of ophthalmic lenses, inorganic glasses arebeing overtaken by organic glasses, particularly in plastic lenses.Under these circumstances, the plastic lens is required to be morelightweight and easier to mold.

[0005] Representative examples of the resin conventionally used as a rawmaterial for plastic lenses include polystyrene resin, polycarbonateresin, polymethyl methacrylate resin and polydiethylene glycol bis(allylcarbonate) resin. The physical properties and production methods ofthese resins have been long known and are described in detail, forexample, in Plastic Age, Vol. 35, pp. 198-202 (1989).

[0006] In this publication, the properties of the plastic lenses derivedfrom various resins are described as follows. The plastic lens derivedfrom polystyrene resin has a problem in that a sufficiently high valuecannot be obtained with respect to birefringence and light scattering,though the refractive index is high. The plastic lens derived frompolycarbonate resin is disadvantageously inferior in resistance againsta solvent or scratching, though the impact resistance is high. In theplastic lens derived from polymethyl methacrylate resin, the refractiveindex is low and the impact resistance is not at a satisfactory level.

[0007] Other than these, a plastic lens derived from polydiethyleneglycol bis(allyl carbonate) resin is known (see, for example, EuropeanPatent Publication No. 0473163A). This plastic lens is favored withexcellent properties particularly as a plastic lens for eyeglasses, suchas superior impact resistance and high Abbe number, therefore, is mostfrequently used despite its low refractive index of 1.498.

[0008] The polydiethylene glycol bis(allyl carbonate) resin is alsoadvantageous in that the polymerization reaction proceeds at a low speedas compared with acrylic resin, therefore, the polymerization reactionis easy to control and a uniform polymerization reaction can be attainedand, as a result, the plastic lens derived from the polydiethyleneglycol bis(allyl carbonate) resin is advantageously reduced in opticalstrain.

[0009] Furthermore, the plastic lens derived from polydiethylene glycolbis(allyl carbonate) resin is known to have dyeability such that whenthe lens is dyed according to a general technique of dipping a plasticlens obtained by cast-molding in a dye bath at a high temperature, thedyeing density is higher than those of plastic lenses derived from otherresins.

[0010] In general, a plastic lens is manufactured by so-called castpolymerization where a monomer is polymerized using two glass molds. Themolds must be cleaned after the cast-molding and the cleaning is usuallyperformed using a strong alkaline solution or a strong acid. Unlikemetal, glass is scarcely changed in quality by cleaning, therefore,glass is preferably used. Furthermore, glass can be easily polished andthereby extremely reduced in surface roughness.

[0011] The polymerization process generally incurs curing shrinkage. Onthe other hand, the lens must perfectly take after the curve on theglass surface and to this purpose, the monomer is required to exhibitgood adhesion to the glass during the polymerization.

[0012] If the curing shrinkage in percentage is excessively large,cracks may be generated on the lens when the curing speed is increased,or the lens or the mold may be damaged at the release of lens from themold. This phenomenon randomly occurs in the production of lenses. Inthe case of plastic lenses derived from polyethylene glycol bis(allylcarbonate) resin, the loss ascribable to this phenomenon usually reachesseveral % of the production of plastic lenses.

DISCLOSURE OF INVENTION

[0013] It is an object of the present invention to provide a compounduseful as a plastic lens material capable of providing a cured producthaving a high Abbe number and a relatively small curing shrinkage, aproduction process of the compound, a plastic lens compositioncontaining the compound, a plastic lens obtained by curing thecomposition, and a production process of the plastic lens.

[0014] As a result of extensive investigation to solve theabove-described problems, the present inventors have found that by usinga (meth)ally ester-based compound containing an alicyclic structure, aplastic lens material capable of providing a cured product having a highAbbe number and a relatively small curing shrinkage can be obtained. Thepresent invention has been accomplished based on this finding.

[0015] More specifically, the present invention (I) is a material forplastic lenses, comprising at least one group represented by thefollowing formula (1) as a terminal group and a group represented by thefollowing formula (2) as a repeating unit:

[0016] wherein each R¹ independently represents an allyl group or amethallyl group and each A¹ independently represents an organic residuederived from a dicarboxylic acid or a carboxylic anhydride.

[0017] wherein each A² independently represents an organic residuederived from a dicarboxylic acid or a carboxylic anhydride and each Xindependently represents an organic residue derived from a polyhydricalcohol having from 2 to 3 hydroxyl groups and containing an alicyclicstructure within the molecule, provided that by the ester bonding, X canhave a branched structure having a group of the above formula (1) as aterminal group and a group of the above formula (2) as a repeating unit.

[0018] The present invention (II) is a process for producing thematerial of the present invention (I), comprising a step oftransesterifying at least one member selected from the group consistingof compounds represented by the following formula (3) with thepolyhydric alcohol described above with respect to the present invention(I) in the presence of a catalyst to obtain a plastic lens material.

[0019] wherein A represents an organic residue derived from adicarboxylic acid or a carboxylic anhydride, and R⁴ and R⁵ eachindependently represents an allyl group or a methallyl group.

[0020] The present invention (III) relates to a composition for plasticlenses, comprising at least one material of the present invention (I).

[0021] The present invention (IV) is a composition for plastic lenses,comprising from 0.1 to 10 parts by mass of at least one radicalpolymerization initiator and 100 parts by mass of the composition forplastic lenses of the present invention (III).

[0022] The present invention (V) is a plastic lens obtained by curingthe composition for plastic lenses of the present invention (III) or thepresent invention (IV).

[0023] The present invention (VI) is a process for producing the plasticlens of the present invention (V).

BRIEF DESCRIPTION OF DRAWINGS

[0024] The figures attached hereto are a 400 MHz ¹H-NMR spectrum chartand an FT-IR spectrum chart of each compound for plastic lens materialsdescribed in Examples.

[0025]FIG. 1 is a 400 MHz ¹H-NMR spectrum chart of the allyl estercompound produced in Production Example 1.

[0026]FIG. 2 is a FT-IR spectrum chart of the allyl ester compoundproduced in Production Example 1.

[0027]FIG. 3 is a 400 MHz ¹H-NMR spectrum chart of the allyl estercompound produced in Production Example 2.

[0028]FIG. 4 is an FT-IR spectrum chart of the allyl ester compoundproduced in Production Example 2.

[0029]FIG. 5 is a 400 MHz ¹H-NMR spectrum chart of the allyl estercompound produced in Production Example 3.

[0030]FIG. 6 is an FT-IR spectrum chart of the allyl ester compoundproduced in Production Example 3.

[0031]FIG. 7 is a 400 MHz ¹H-NMR spectrum chart of the allyl estercompound produced in Production Example 4.

[0032]FIG. 8 is an FT-IR spectrum chart of the allyl ester compoundproduced in Production Example 4.

BEST MODE FOR CARRYING OUT THE INVENTION

[0033] The present invention is described in detail below.

[0034] First, the material of the present invention (I) is described.The present invention (I) is a material for plastic lenses, comprisingat least one group represented by the following formula (1) as aterminal group and a group represented by the following formula (2) as arepeating unit:

[0035] wherein each R¹ independently represents an allyl group or amethallyl group and each A¹ independently represents an organic residuederived from a dicarboxylic acid or a carboxylic anhydride.

[0036] wherein each A² independently represents an organic residuederived from a dicarboxylic acid or a carboxylic anhydride and each Xindependently represents an organic residue derived from a polyhydricalcohol having from 2 to 3 hydroxyl groups and containing an alicyclicstructure within the molecule, provided that, by the ester bonding, Xcan have a branched structure having a group of the above formula (1) asa terminal group and a group of the above formula (2) as a repeatingunit.

[0037] In formula (1), each R¹ independently represents an allyl groupor a methallyl group. Also, in formula (1), each A¹ independentlyrepresents an organic residue derived from a dicarboxylic acid or acarboxylic anhydride. In formula (2), each A² independently representsan organic residue derived from a dicarboxylic acid or a carboxylicanhydride. Also, in formula (2), each X independently represents anorganic residue derived from a polyhydric alcohol having from 2 to 3hydroxyl groups and containing an alicyclic structure within themolecule.

[0038] The term “each R¹ independently represents an allyl group or amethallyl group” as used herein means that the moiety represented by R¹of the terminal group represented by formula (1) in the material of thepresent invention (I) all may be occupied by an allyl group or amethallyl group or may be partially occupied by an allyl group with theremaining by a methallyl group.

[0039] A¹ in Formula (1) and A² in formula (2) each represents anorganic residue derived from a dicarboxylic acid or a carboxylicanhydride.

[0040] Examples of the dicarboxylic acid or carboxylic anhydride includealiphatic dicarboxylic acids and anhydrides thereof, such as succinicacid and succinic anhydride, glutaric acid and glutaric anhydride,adipic acid, malonic acid and malonic anhydride, and 2-methylsuccinicacid and 2-methylsuccinic anhydride dicarboxylic acids having analicyclic structure and anhydrides thereof, such as1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,1,2-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylicanhydride, and 4-methylcyclohexane-1,2-dicarboxylic acid and4-methylcyclohexane-1,2-dicarboxylic anhydride and aromatic dicarboxylicacids and anhydrides thereof, such as terephthalic acid, isophthalicacid, and phthalic acid and phthalic anhydride. Needles to say, thepresent invention is not limited to these specific examples.

[0041] Among those, in view of the fluidity of the compound, preferredare glutaric acid, succinic acid, adipic acid, 2-methylsuccinic acid and1,3-cyclohexanedicarboxylic acid, and more preferred are glutaric acid,2-methylsuccinic acid, adipic acid and succinic acid.

[0042] The term “each A¹ independently represents an organic residuederived from a dicarboxylic acid or a carboxylic anhydride” or “each A²independently represents an organic residue derived from a dicarboxylicacid or a carboxylic anhydride” as used herein means that the moietyrepresented by A¹ of the terminal group represented by formula (1) inthe material of the present invention (I) and the moiety represented byA² of the repeating unit represented by formula (2) in the material ofthe present invention (I) (hereinafter “A¹” and “A²” are collectivelyreferred to as “A”) each may be entirely occupied by organic residuesderived from dicarboxylic acids or carboxylic anhydrides having the samestructure, may be occupied by organic residues derived from dicarboxylicacids or carboxylic anhydrides having different structures, or may bepartially occupied by organic residues derived from dicarboxylic acidshaving the same structure with the remaining by organic residues derivedfrom dicarboxylic acids having different structures.

[0043] More specifically, in the following structural formula (4) whichis one example of the material of the present invention (I), As in thenumber of k contained in the repeating structure are independent of eachother.

[0044] wherein each A independently represents an organic residuederived from a dicarboxylic acid, k represents an integer of 2 to 3, andX represents an organic residue derived from a polyhydric alcohol havingfrom 2 to 3 hydroxyl groups and containing an alicyclic structure withinthe molecule.

[0045] In structural formula (4), the As, in the number k, all may beorganic residues derived from dicarboxylic acids having differentstructures (that is, organic residues are derived one by one fromdicarboxylic acids having k kinds of structure) or all may be organicresidues derived from dicarboxylic acid having the same structure (thatis, organic residues in the number of k are derived from dicarboxylicacids having one kind of structure). A mixed structure where some of As,in the number k, are organic residues derived from dicarboxylic acidshaving the same structure and some others are organic residues derivedfrom dicarboxylic acids having different kinds of structure may also beused.

[0046] The term “each X independently represents” as used herein meansthat in the following structural formula (5) as one example of therepeating unit represented by formula (2), the Xs, in the number m,contained in the repeating structure are independent of each other.

[0047] wherein each X independently represents an organic residuederived from a polyhydric alcohol having from 2 to 3 hydroxyl groups andcontaining an alicyclic structure within the molecule, m represents 0 oran integer of 1 or more, and when m is an integer of 1 or more, nrepresents 0 or an integer of 1 or more and each A independentlyrepresents an organic residue derived from a dicarboxylic acid.

[0048] For example, in structural formula (5), the Xs, in the number m,all may be organic residues derived from different polyhydric alcohols(that is, organic residues are derived one by one from m kinds ofpolyhydric alcohol) or all may be organic residues derived from the samekind of polyhydric alcohol (that is, organic residues in the number of mare derived from one kind of polyhydric alcohol). A mixed structurewhere some of the Xs, in the number m, are organic residues derived fromthe same kind of polyhydric alcohol and some others are organic residuesderived from different kinds of polyhydric alcohol may also be used.Moreover, in this mixed structure, all may be completely random or apart may be repeated.

[0049] By the ester bonding, X can have a branched structure containingthe formula (1) as a terminal group and the formula (2) as a repeatingunit. More specifically, for example, when an organic residue derivedfrom cyclohexane-1,2,4-trimethanol, which is one example of thetrihydric saturated alcohol, is present in X, the material of thepresent invention (I) can have a partial structure represented by thefollowing structural formula (6).

[0050] Each X is of course independently an organic residue derived froma polyhydric alcohol having from 2 to 3 hydroxyl groups and containingan alicyclic structure within the molecule. Also, each A isindependently an organic residue derived from a dicarboxylic acid.

[0051] In formula (2), each X independently represents an organicresidue derived from a polyhydric alcohol having from 2 to 3 hydroxylgroups and containing an alicyclic structure within the molecule.Examples of the polyhydric alcohol having from 2 to 3 hydroxyl groupsand containing an alicyclic structure within the molecule include thefollowing compounds. Needless to say, however, the present invention isnot limited to these specific examples.

[0052] A dihydric alcohol represented by the following formula (14) mayalso be used.

[0053] wherein each R² independently represents at least one memberselected from the organic groups represented by the following structuralformulae (15) to (17), each R³ independently represents at least onemember selected from the organic residues represented by the followingstructural formulae (18) to (20), a and b each independently represents0 or an integer of 1 to 10, and Y represents an organic group selectedfrom the following structural formulae (21) and (22).

[0054] In formula (14), the term “each R² independently represents atleast one member selected from the organic groups” means that R²s in thenumber of a all may be organic groups having the same structure, all maybe organic groups having different structures, or may be partiallyorganic groups having the same structure with the remaining beingorganic groups having different structures, where, however, R² must beselected from the organic groups represented by structural formulae (15)to (17).

[0055] In formula (14), the term “each R³ independently represents atleast one member selected from the organic residues” means that R³s inthe number of b all may be organic groups having the same structure, allmay be organic groups having different structures or may be partiallyorganic groups having the same structure with the remaining beingorganic groups having different structures, where, however, R³ must beselected from the organic groups represented by structural formulae (18)to (20).

[0056] In formula (14), a and b each independently represents 0 or aninteger of 1 to 10. Y represents an organic group selected from thefollowing structural formulae (21) and (22).

[0057] Specific examples of the dihydric alcohol represented by formula(14) include 2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane,2,2-bis[4-(2-hydroxypropoxy)cyclohexyl]propane, 3 mol ethylene oxideadducts of 2,2-bis(4-hydroxycyclohexyl)propane, 4 mol propylene oxideadducts of (4-hydroxycyclohexyl)propane,bis[4-(2-hydroxyethoxy)cyclohexyl]methane,bis[4-(2-hydroxypropoxy)cyclohexyl]methane, 3 mol ethylene oxide adductsof bis(4-hydroxycyclohexyl)methane, and 4 mol propylene oxide adducts ofbis(4-hydroxycyclohexyl)methane. Needless to say, however, the presentinvention is not limited to these specific examples.

[0058] Among these polyhydric alcohols, since raw materials are easilyavailable, the compounds of structural formula (7), structural formula(8) and structural formula (9), and2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane,2,2-bis[4-(2-hydroxypropoxy)cyclohexyl]propane and 3 mol ethylene oxideadducts of 2,2-bis(4-hydroxycyclohexyl)propane are preferred, and thecompound of structural formula (7),2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane,2,2-bis[4-(2-hydroxypropoxy)cyclohexyl]propane and 3 mol ethylene oxideadducts of 2,2-bis(4-hydroxycyclohexyl)propane are more preferred.

[0059] The repeating number of the group represented by formula (2)which is a repeating unit of the material of the present invention (I)is not particularly limited. A mixture of materials having variousrepeating numbers may also be used. Furthermore, a material where therepeating number is 0 and a material where the repeating number is aninteger of 1 or more may be used in combination. However, use of only acompound where the repeating number is 0 is disadvantageous in achievingthe object of the present invention.

[0060] Usually, the repeating number of the group represented by formula(2) as a repeating unit of the material of the present invention (I) ispreferably an integer of from 0 to 50. If a plastic lens materialcomprising only compounds where the repeating number exceeds 50 is usedfor a plastic lens composition, the allyl group concentration decreasesand this may cause adverse effects, for example, at the time of curing,the curing may be retarded or a part of the compound may remain uncuredto reduce the physical properties of the cured product such asmechanical properties. In all compounds contained in the plastic lensmaterial, the repeating number is preferably an integer of 0 to 50, morepreferably from 0 to 30, still more preferably from 0 to 10.

[0061] Depending of the production conditions, the compound representedby formula (3) as a raw material may remain in the material of thepresent invention (I) but the material may be used as it is as a plasticlens material. However, when the present invention (I) is used as aplastic lens material, it is disadvantageous for reducing the curingshrinkage in percentage that the compound represented by formula (3) ispresent in a proportion of 90% by mass or more based on the entirecurable component.

[0062] Incidentally, the term “entire curable component” as used in thepresent invention means the total amount of the material of the presentinvention (I) and a monomer copolymerizable with at least one materialof the present (I).

[0063] The present invention (II) is described below. The presentinvention (II) is a process for producing the material of the presentinvention (I), comprising a step of transesterifying at least one memberselected from the group consisting of compounds represented by formula(3) with a polyhydric alcohol in the presence of a catalyst to obtain acompound for the plastic lens material.

[0064] In formula (3), R⁴ and R⁵ each independently represents an allylgroup or a methallyl group.

[0065] Furthermore, in formula (3), A represents an organic residuederived from a dicarboxylic acid or a carboxylic anhydride. Thedicarboxylic acid and carboxylic anhydride include aliphaticdicarboxylic acids and anhydrides thereof, such as succinic acid andsuccinic anhydride, glutaric acid and glutaric anhydride, adipic acid,malonic acid and malonic anhydride, and 2-methylsuccinic acid and2-methylsuccinic anhydride; dicarboxylic acids having an alicyclicstructure and anhydrides thereof, such as 1,4-cyclohexanedicarboxylicacid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acidand 1,2-cyclohexanedicarboxylic anhydride, and4-methylcyclohexane-1,2-dicarboxylic acid and4-methylcyclohexane-1,2-dicarboxylic anhydride; and aromaticdicarboxylic acids and anhydrides thereof, such as terephthalic acid,isophthalic acid, and phthalic acid and phthalic anhydride. Needles tosay, however, the present invention is not limited to these specificexamples.

[0066] The compound of the material of the present invention (I) can beproduced, for example, by the following process.

[0067] The objective compound can be obtained using at least onecompound represented by formula (3) in a constant ratio through a stepof transesterifying these compounds with at least one polyhydric alcoholhaving from 2 to 3 hydroxyl groups and containing an alicyclic structurewithin the molecule in the presence of a catalyst. Of course, thepresent invention is not limited thereto and a step such as purificationmay be included, if desired.

[0068] The catalyst for use in the above-described step is notparticularly limited as long as it is a catalyst capable of being usedfor transesterification in general. An organic metal compound isparticularly preferred and specific examples thereof includetetraisopropoxy titanium, tetrabutoxy titanium, dibutyltin oxide,dioctyltin oxide, hafnium acetylacetonate and zirconium acetylacetonate,however, the present invention is not limited thereto. Among these,dibutyltin oxide and dioctyltin oxide are preferred.

[0069] The reaction temperature in this step is not particularly limitedbut is preferably from 100 to 230° C., more preferably 120 to 200° C. Inthe case where a solvent is used, the reaction temperature is sometimeslimited by the boiling point of the solvent.

[0070] In this step, a solvent is usually not used, however a solventmay be used, if desired. The solvent which can be used is notparticularly limited as long as it does not inhibit thetransesterification. Specific examples thereof include benzene, toluene,xylene and cyclohexane, however, the present invention is not limitedthereto. Among these, benzene and toluene are preferred. However, asdescribed above, the step may be performed without using a solvent.

[0071] The composition for plastic lenses of the present invention (III)or the present invention (IV) is described below.

[0072] The present invention (III) is a composition for plastic lenses,comprising at least one compound of the material of the presentinvention (I).

[0073] The amount of the compound of the material of the presentinvention (I) blended is preferably from 5 to 80% by mass, morepreferably from 15 to 70% by mass, based on the entire curable componentcontained in the composition for plastic lenses of the present invention(III). If the amount of the material blended is less than 5% by mass,the two requirements of high Abbe number and low curing shrinkage canseldom be satisfied at the same time and this is not preferred.

[0074] For the purpose, mainly, of adjusting the viscosity of thecomposition, one or more compounds copolymerizable with the compound ofthe material of the present invention (I) may be added to the presentinvention (III).

[0075] Examples of the compound include monomers having an acryl group,a vinyl group or an allyl group. Specific examples of the monomer havingan acryl group include methyl (meth)acrylate and isobornyl(meth)acrylate, and specific examples of the monomer having a vinylgroup include vinyl acetate and vinyl benzoate, and specific examples ofthe monomer having an allyl group include the compounds having astructural formulae (23) to (29) shown below. In addition, polyethyleneglycol bis(allyl carbonate) resin represented by CR-39 (trade name,produced by PPG) may also be used. Of course, the present invention isnot limited to these specific examples and diallyl phthalate, diallylterephthalate, diallyl isophthalate, allyl benzoate and the like mayalso be used within the range of not impairing the physical propertiesof the plastic lens obtained by curing.

[0076] Specific examples of the compound which is preferably usedinclude the compounds represented by the following structural formulae(23) to (29) and polyethylene glycol bis(allyl carbonate) resin.

[0077] The amount of the compound added greatly varies depending on themonomer used, however, the amount added is usually 90% by mass or less,preferably 80% by mass or less, more preferably 75% by mass or less,based on the entire curable component contained in the plastic lenscomposition of the present invention. If the compound is added in excessof 90% by mass, the two requirements for the plastic lens of the presentinvention, namely, high Abbe number and low curing shrinkage, aredifficult to attain at the same time and this is not preferred.

[0078] With respect to other effects, when the plastic lens material ofthe present invention is added in an amount of 0.5% by mass or more topolyethylene glycol bis(allyl carbonate) resin, the uneven dyeing whichappears at the dyeing of polyethylene glycol bis(allyl carbonate) resincan be reduced.

[0079] An optimal monomer is selected by taking account of the kinds andthe mixing ratios of the above-described compound and the allyl esteroligomer contained in the resin composition for plastic lenses and thephysical property values such as optical property required for theplastic lens obtained by curing the composition.

[0080] On taking account of operability in the casting, the viscosity ofthe plastic lens composition of the present invention (III) is generally3,000 mPa.s or less at 25° C., preferably 1,000 mPa.s or less, morepreferably 500 mPa.s or less.

[0081] The term “viscosity” as used herein is a viscosity measured by arotational viscometer. The rotational viscometer is described in detailin Iwanami Rikagaku Jiten (Iwanami Physics and Chemistry Encyclopedia),3rd ed., 8th imp. (Jun. 1, 1977).

[0082] The present invention (IV) is a composition for plastic lenses,comprising from 0.1 to 10 parts by mass of at least one radicalpolymerization initiator per 100 parts by mass of the composition forplastic lenses of the present invention (III).

[0083] The plastic lens composition of the present invention (IV) maycontain a radical polymerization initiator as a curing agent and this ispreferred.

[0084] The radical polymerization initiator which can be added to theplastic lens composition of the present invention (IV) is notparticularly limited and a known radical polymerization initiator may beadded as long as it does not adversely affect the physical propertyvalues such as optical property of the plastic lens obtained by curingthe composition.

[0085] The radical polymerization initiator for use in the presentinvention is, however, preferably a radical polymerization initiatorwhich is soluble in other components present in the composition to becured and which generates free radicals at 30 to 120° C. Specificexamples of the radical polymerization initiator which can be addedinclude diisopropylperoxy dicarbonate, dicyclohexylperoxy dicarbonate,di-n-propylperoxy dicarbonate, di-sec-butylperoxy dicarbonate andtert-butyl perbenzoate, but the present invention is not limitedthereto. In view of the curability, diisopropylperoxy dicarbonate ispreferred.

[0086] The amount of the radical polymerization initiator added is inthe range from 0.1 to 10 parts by mass, preferably from 1 to 5 parts bymass, per 100 parts by mass of the entire curable component contained inthe plastic lens composition of the present invention (III). If theamount added is less than 0.1 part by mass, curing of the compositionmay proceed insufficiently, whereas if it exceeds 10 parts by mass, theprofitability decreases and this is not preferred.

[0087] The plastic lens composition of the present invention (III) orthe present invention (IV) may contain additives commonly used for thepurpose of improving the performance of the plastic lens, such as acoloring agent including dye and pigment, an ultraviolet absorbent, amold-releasing agent and an antioxidant.

[0088] Examples of the coloring agent include organic pigments such asanthraquinone type, azo type, carbonium type, quinoline type,quinoneimine type, indigoid type and phthalocyanine type; organic dyessuch as azoic dye and sulfur dye; and inorganic pigments such astitanium yellow, yellow iron oxide, zinc yellow, chrome orange,molybdenum red, cobalt violet, cobalt blue, cobalt green, chromic oxide,titanium oxide, zinc sulfide and carbon black.

[0089] Examples of the mold-releasing agent include stearic acid, butylstearate, zinc stearate, stearic acid amide, fluorine-containingcompounds and silicone compounds.

[0090] Examples of the ultraviolet absorbent include triazoles such as2-(2′-hydroxy-tert-butylphenyl)benzotriazole, benzophenones such as2,4-dihydroxybenzophenone, salicylates such as 4-tert-butylphenylsalicylate, and hindered amines such asbis-(2,2,6,6-tetramethyl-4-piperidinyl)sebacate.

[0091] Examples of the antioxidant include phenols such as2,6-di-tert-butyl-4-methylphenol andtetrakis[methylene-3-(3′,5′-di-tert-butyl-4-hydroxyphenyl)propionate]methane;sulfurs such as dilauryl-3,3′-thiodipropionate; andphosphorus-containing antioxidants such as trisnonylphenylphosphite.

[0092] The total amount of the additives added, such as a coloring agentincluding dye and pigment, an ultraviolet absorbent, a mold-releasingagent and an antioxidant, is preferably 1% by mass or less based on theentire curable resin component contained in the resin composition forplastic lenses of the present invention.

[0093] The present invention (V) is described below. The presentinvention (V) is a plastic lens obtained by curing the plastic lenscomposition of the present invention (III) or the present invention(IV).

[0094] The curing shrinkage in percentage of the plastic lens in thepresent invention is preferably 10.0% or less at 23° C. The reasontherefor is that if the curing shrinkage in percentage on curing isexcessively large, cracks are readily generated during the curing and,as a result, the yield at the molding decreases.

[0095] Finally, the present invention (VI) is described. The presentinvention (VI) is a process for producing the plastic lens of thepresent invention (V), comprising curing the plastic lens composition ofthe present invention (III) or the present invention (IV).

[0096] In the present invention, the mold-working of the plastic lenscomposition is suitably performed by cast-molding. Specifically, amethod of adding a radical polymerization initiator to the composition,injecting the mixture through a line into a mold fixed by an elastomergasket or a spacer, and curing it under heating in an oven may be used.

[0097] The constructive material of the mold used here is a metal orglass. In general, the mold for plastic lenses must be cleaned after thecast-molding and such cleaning is usually performed using a strongalkali solution or a strong acid. Unlike metal, glass is scarcelychanged in the quality by the cleaning and furthermore, glass can beeasily polished and thereby extremely reduced in the surface roughness,therefore, glass is preferably used.

[0098] The plastic lens composition of the present invention (III) orthe present invention (IV) has an alicyclic structure, accordingly,depending on the molecular design, the refractive index can be easilyapproximated to the refractive index 1.498 of the plastic lens startingfrom polydiethylene glycol bis(allyl carbonate) which is used forplastic lenses in many cases. This is advantageous in that the mold orthe like conventionally used in the molding need not be changed but canbe used as it is.

[0099] The curing temperature at the molding is from about 30 to 120°C., preferably from 40 to 100° C. With respect to the operation ofcuring temperature, on taking account of shrinkage or strain at thecuring, a method of allowing the curing to gradually proceed whileelevating the temperature is preferably used. The curing time isgenerally from 0.5 to 100 hours, preferably from 3 to 50 hours, morepreferably from 10 to 30 hours.

[0100] The method for dyeing the plastic lens of the present inventionis not particularly limited. Any method may be used as long as it is aknown dyeing method for plastic lenses. Among these, a dip dyeing methodconventionally known as a general method is preferred. The “dip dyeingmethod” as used herein means a method of dispersing a disperse dyetogether with a surfactant in water to prepare a dye bath and dipping aplastic lens in this dyeing solution under heating, thereby dyeing theplastic lens.

[0101] The method for dyeing the plastic lens is not limited to this dipdyeing method but other known methods may be used, for example, a methodof sublimating an organic pigment and thereby dyeing a plastic lens(see, Japanese Examined Patent Publication No. 35-1384, JP-B-35-1384) ora method of sublimating a sublimable dye and thereby dyeing a plasticlens (see, Japanese Examined Patent Publication Nos. 56-159376 and1-277814, JP-B-56-159376 and JP-B-1-277814) may be used. In view ofsimple operation, the dip dyeing method is most preferred.

[0102] The present invention is further illustrated below by referringto the following examples, however, the present invention should not beconstrued as being limited thereto.

[0103] Various physical properties were measured as follows.

[0104] 1. Refractive Index (n_(D)) and Abbe Number (ν_(D))

[0105] A test piece of 9 mm×16 mm×4 mm was prepared and measured on therefractive index (n_(D)) and Abbe number (ν_(D)) at 25° C. using “AbbeRefractometer 1T” manufactured by Atago. The contact solvent used wasα-bromonaphthalene.

[0106] 2. Viscosity

[0107] In Example 1, Examples 3 to 6, Examples 8 to 15, and ComparativeExamples 1 to 5, 300 g of the specimen was charged into a 300-ml tallbeaker. The viscosity of them was measured at 25° C. and at 20 rpm usingNo. 1 rotor by B-Type Viscometer (Model BH) manufactured by Tokyo KeikiCo., Ltd.

[0108] In Example 2 and Example 7, 5.2 ml of the specimen was chargedinto a designated sample adapter. The viscosity of them was measured at25° C. at 100 rpm using an HH-1 rotor by B-Type Viscometer (Model B8U)manufactured by Tokyo Keiki Co., Ltd.

[0109] 3. Barcol Hardness

[0110] The Barcol hardness was measured using Model 934-1 according toJIS K 6911.

[0111] 4. Measurement of Curing Shrinkage in Percentage

[0112] The value of curing shrinkage in percentage (%) was calculatedusing the following formula from the specific gravity of the compositionbefore curing and the specific gravity of the cured product.

[0113] Curing Shinkage in Percentage (%)=(1−(specific gravity ofcomposition before curing/specific gravity of cured product))×100

[0114] At this time, the specific gravity of the composition beforecuring was measured by a specific gravity bottle at a measuringtemperature of 23° C. according to the measuring method for specificgravity (see, JIS Z 8804). The specific gravity after curing wasmeasured by a sink-float method (at 23° C.) (see, JIS K 7112).

[0115] 5. Dyeing Method and Evaluation of Uneven Dyeing

[0116] To a 1 l beaker, 0.8 g of Sumikaron Blue E-FBL (produced bySumitomo Chemical Co., Ltd.) and 0.5 L of water were added and dissolvedwith stirring. The resulting solution was heated in a water bath at 80°C. and into this disperse dye solution, cured plastic lens samples eachfixed to a holder so as not to overlap one on another were dipped at 80°C. for 10 minutes. Thereafter, the samples were taken out, thoroughlywashed with water and then hot-air dried in an oven at 30° C.

[0117] The thus-obtained dyed plastic lens samples were observed with aneye and those failed in having a uniformly dyed appearance and revealedto have uneven dyeing were rated “defective”. By evaluating 30 curedsamples in total, the number of “defective” samples was counted.

PRODUCTION EXAMPLE 1

[0118] Into a 500 ml three-neck flask with a distillation unit, 160.2 gof dimethyl glutarate, 232.3 g of allyl alcohol, 0.27 g of potassiumacetate and 1.33 g (1% by mass based on dimethyl glutarate) of calciumhydroxide were charged. The system was heated at a bath temperature of110 to 120° C. in a nitrogen stream, and methanol generated wasdistilled off. The reaction was continued until a theoretical amount ofmethanol was distilled off, and when 64 g (100% based on the theoreticaldistillation amount of methanol) was distilled off, the reactor wascooled. The resulting reaction solution was purified by distillationunder reduced pressure, as a result, 200 g of diallyl glutarate wasobtained as a colorless transparent liquid (isolation yield: 95%, rawmaterial: 1 mol).

[0119] Into a 300 ml three-neck flask with a distillation unit, 101 g(0.48 mol) of diallyl glutarate, 53.8 g (0.373 mol) of 1,4-cyclohexanedimethanol and 0.1 g (1% by mass based on diallyl glutarate) ofdibutyltin oxide were charged. The system was heated at 180° C. in anitrogen stream, and the allyl alcohol generated was distilled off. Whenabout 26 g of allyl alcohol was distilled off, the pressure within thereaction system was reduced to 1.33 kPa to increase the distillationrate of allyl alcohol. After a theoretical amount (43.6 g) of allylalcohol was distilled off, the system was heated for another one hourand then kept at 190° C. and 0.13 kPa for one hour. Thereafter, thereactor was cooled, as a result, 110 g of an allyl ester compound wasobtained (hereinafter referred to as “Sample A”). FIG. 1 and FIG. 2 show400 MHz ¹H-NMR spectrum (solvent: CDCl₃) and FT-IR spectrum of Sample A,respectively.

[0120] In FIG. 1, the peak in the vicinity of 0.9 to 2.0 ppm isattributable to a proton derived from cyclohexane ring, the peak in thevicinity of 2.3 to 2.5 ppm is attributable to a proton derived fromglutaric acid skeleton, the peak in the vicinity of 3.7 to 4.1 ppm isattributable to a proton of methylene derived from cyclohexanedimethanolwhich is ester-bonded, the peak in the vicinity of 4.6 ppm isattributable to a proton of methylene at the allyl position, the peak inthe vicinity of 5.3 ppm is attributable to a proton in the terminal ofthe double bond at the allyl position, and the peak in the vicinity of5.8 ppm is attributable to a proton in the inner side of the double bondat the allyl position.

[0121] In FIG. 2, the peak at 1738 cm⁻¹ is absorption by the carbonylstretching vibration of the carboxyl group.

[0122] Sample A was analyzed by gas chromatography (GC-14B manufacturedby Shimadzu Corp., hydrogen flame ionization detector, column used:OV-17 of 0.5 m, the temperature condition: 160° C. and constant) andfound to contain 3.88% by mass of diallyl glutarate.

PRODUCTION EXAMPLE 2

[0123] Into a 3 l three-neck flask with a distillation unit, 660.6 g ofsuccinic anhydride, 1,056 g of allyl alcohol, 1,000 ml of benzene and6.61 g (1% by mass based on succinic anhydride) of concentrated sulfuricacid were charged. The system was heated at 100° C. in a nitrogenstream, and H₂O generated was distilled off. The reaction was continueduntil a theoretical amount of H₂O was distilled off and when 109 g (100%based on the theoretical distillation amount of H₂O) of H₂O wasdistilled off, the reactor was cooled. The resulting reaction solutionwas neutralized with an aqueous NaOH solution and washed with water.After benzene and excess allyl alcohol were distilled off, the reactionsolution was purified by distillation under reduced pressure, as aresult, 1,130 g of diallyl succinate was obtained as a colorlesstransparent liquid.

[0124] Into a 3 l three-neck flask with a distillation unit, 1,784 g ofdiallyl succinate, 829 g of 1,4-cyclohexanedimethanol and 1.784 g (1% bymass based on diallyl succinate) of dibutyltin oxide were charged. Thesystem was heated at 180° C. in a nitrogen stream and the allyl alcoholgenerated was distilled off. When about 418 g of allyl alcohol wasdistilled off, the pressure within the reaction system was reduced to1.33 kPa to increase the distillation rate of allyl alcohol. After atheoretical amount (618 g) of allyl alcohol was distilled off, thesystem was heated for another one hour and then kept at 190° C. and 0.13kPa for one hour. Thereafter, the reactor was cooled, as a result, 1,897g of an allyl ester compound was obtained (hereinafter referred to as“Sample B”). FIG. 3 and FIG. 4 show 400 MHz ¹H-NMR spectrum (solvent:CDCl₃) and FT-IR spectrum of Sample B, respectively.

[0125] In FIG. 3, the peak in the vicinity 0.9 to 2.0 ppm isattributable to a proton derived from a cyclohexane ring, the peak inthe vicinity 2.6 to 2.7 ppm is attributable to a proton derived from asuccinic acid skeleton, the peak in the vicinity 3.9 to 4.2 ppm isattributable to a proton of methylene derived from cyclohexanedimethanolwhich is ester-bonded, the peak in the vicinity 4.5 ppm is attributableto a proton of methylene at the allyl position, the peak in the vicinity5.3 ppm is attributable to a proton in the terminal of the double bondat the allyl position, and the peak in the vicinity 5.9 ppm isattributable to a proton in the inner side of the double bond at theallyl position.

[0126] In FIG. 4, the peak of 1736 cm⁻¹ is absorption by the carbonylstretching vibration of the carboxyl group.

[0127] Sample B was analyzed by gas chromatography (GC-14B: manufacturedby Shimadzu Corp., hydrogen flame ionization detector, column used:OV-17 of 0.5 m, temperature condition: 160° C. and constant) and foundto contain 11.8% by mass of diallyl succinate.

PRODUCTION EXAMPLE 3

[0128] Into a 1 l three-neck flask with a distillation unit, 1,000 g ofdimethyl 2-methylsuccinate, 1,441 g of allyl alcohol, 25 g of potassiumacetate and 5 g of calcium hydroxide were charged. The system was heatedat 110° C. in a nitrogen stream, and methanol generated was distilledoff. The reaction was continued until a theoretical amount of methanolwas distilled off and when 385.7 g (97%) was distilled off, the reactorwas cooled. The resulting reaction solution was filtered by suctionusing a No. 5C Kiriyama funnel to separate the solid matters in thereaction solution. Thereafter, the solution was purified by distillationunder reduced pressure, as a result, 1,200 g of diallyl2-methylsuccinate was obtained as a colorless transparent liquid.

[0129] Into a 1 l three-neck flask with a distillation unit, 640 g ofdiallyl 2-methylsuccinate, 336 g of 1,4-cyclohexanedimethanol and 0.639g of dibutyltin oxide were charged. The system was heated at 180° C. ina nitrogen stream and allyl alcohol generated was distilled off. Whenabout 190 g of allyl alcohol was distilled off, the pressure within thereaction system was reduced to 1.33 kPa to increase the distillationrate of allyl alcohol. After a theoretical amount (270.7 g) of allylalcohol was distilled off, the system was heated for another one hourand then kept at 190° C. and 0.13 kPa for one hour. Thereafter, thereactor was cooled and, as a result, 705 g of an allyl ester compoundwas obtained (hereinafter referred to as “Sample C”). FIG. 5 and FIG. 6show 400 MHz ¹H-NMR spectrum (solvent: CDCl₃) and FT-IR spectrum ofSample C, respectively.

[0130] In FIG. 5, the peak in the vicinity of 0.9 to 2.0 ppm isattributable to a proton derived from a cyclohexane ring, with the peakin the vicinity of 1.2 ppm being a peak derived from the branched methylgroup in succinic acid, the peak in the vicinity of 2.4 to 3.0 ppm isattributable to a proton derived from 2-methylsuccinic acid skeleton,the peak in the vicinity of 3.9 to 4.2 ppm is attributable to a protonof methylene derived from cyclohexanedimethanol which is ester-bonded,the peak in the vicinity of 4.6 ppm is attributable to a proton ofmethylene at the allyl position, the peak in the vicinity of 5.3 ppm isattributable to a proton in the terminal of the double bond at the allylposition, and the peak in the vicinity of 5.8 to 6.0 ppm is attributableto a proton in the inner side of the double bond at the allyl position.

[0131] In FIG. 6, the peak of 1738 cm⁻¹ is absorption by the carbonylstretching vibration of the carboxyl group.

[0132] Sample C was analyzed by gas chromatography (GC-14B: manufacturedby Shimadzu Corp., hydrogen flame ionization detector, column used:OV-17 of 0.5 m, temperature condition: 160° C. and constant) and foundto contain 3.8% by mass of diallyl 2-methylsuccinate.

PRODUCTION EXAMPLE 4

[0133] Into a 3 l three-neck flask with a distillation unit, 660.6 g ofsuccinic anhydride, 1,056 g of allyl alcohol, 1,000 ml of benzene and6.61 g (1% by mass based on succinic anhydride) of concentrated sulfuricacid were charged. The system was heated at 100° C. in a nitrogen streamand H₂O generated was distilled off. The reaction was continued until atheoretical amount of H₂O was distilled off and when 109 g (100% basedon the theoretical distillation amount of H₂O) of H₂O was distilled off,the reactor was cooled. The resulting reaction solution was neutralizedwith an aqueous NaOH solution and washed with water. After benzene andexcess allyl alcohol were distilled off, the reaction solution waspurified by distillation under reduced pressure and, as a result, 1,130g of diallyl succinate was obtained as a colorless transparent liquid.

[0134] Into a 1 l three-neck flask with a distillation unit, 396.4 g ofdiallyl succinate, 328.5 g of2,2-bis[4-(2-hydroxyethoxy)cyclohexyl]propane (HBA-2, trade name,produced by Nippon Nyukazai K.K.) and 0.4 g of dibutyltin oxide werecharged. The system was heated at 180° C. in a nitrogen stream and theallyl alcohol generated was distilled off. When about 81.3 g of allylalcohol was distilled off, the pressure within the reaction system wasreduced to 1.33 kPa to increase the distillation rate of allyl alcohol.After a theoretical amount (116.2 g) of allyl alcohol was distilled off,the system was heated for another one hour and then kept at 190° C. and0.13 kPa for one hour. Thereafter, the reactor was cooled and, as aresult, 256 g of an allyl ester compound was obtained (hereinafterreferred to as “Sample D”). FIG. 7 and FIG. 8 show 400 MHz ¹H-NMRspectrum (solvent: CDCl₃) and FT-IR spectrum of Sample D, respectively.

[0135] In FIG. 7, the peak in the vicinity 0.6 to 0.8 ppm isattributable to a proton derived from a propane skeleton, the peak inthe vicinity 0.9 to 2.2 ppm is attributable to a proton derived from acyclohexane ring, the peak in the vicinity 2.6 ppm is attributable to aproton derived from a succinic acid skeleton, the peak in the vicinity3.6 is attributable to a proton of methylene derived fromcyclohexanedimethanol which is ester-bonded, the peak in the vicinity4.6 ppm is attributable to a proton of methylene at the allyl position,the peak in the vicinity 5.3 ppm is attributable to a proton in theterminal of the double bond at the allyl position, and the peak in thevicinity 5.8 to 6.0 ppm is attributable to a proton in the inner side ofthe double bond at the allyl position.

[0136] In FIG. 8, the peak of 1737 cm⁻¹ is absorption by the carbonylstretching vibration of the carboxyl group.

[0137] Sample D was analyzed by gas chromatography (GC-14B: manufacturedby Shimadzu Corp., hydrogen flame ionization detector, column used:OV-17 of 0.5 m, temperature condition: 160° C. and constant) and foundto contain 12.3% by mass of diallyl succinate.

[0138] In the following examples, Samples A to D were diluted so as todecrease the viscosity, using the compound of the following structuralformula (23) or the following structural formula (28).

[0139] The kind and composition of each diluted compound are shown inTable 1.

EXAMPLE 1 Production of Composition for Plastic Lens

[0140] As shown in Table 1, 40.0 parts by mass of the allyl estercompound as Sample A, 60.0 parts by mass of the compound represented bystructural formula (24) and 3 parts by mass of diisopropylperoxydicarbonate (IPP) were blended and mixed with stirring to form acompletely homogeneous solution composition. The viscosity at this timewas measured. Thereafter, a vessel containing this solution was placedin a desiccator capable of depressurization and the pressure was reducedby a vacuum pump for about 15 minutes to deaerate gases in the solution.The resulting solution composition was injected by a syringe into a moldfabricated from a glass-made mold for ophthalmic plastic lenses and aresin-made gasket, while taking care to prevent intermixing of gas, andthen cured in an oven, according to a temperature rising program, underheating at 40° C. for 7 hours, heating at from 40 to 60° C. for 10hours, heating at from 60 to 80° C. for 3 hours, heating at 80° C. for 1hour and heating at 85° C. for 2 hours.

[0141] The lens obtained was measured on the refractive index, Abbenumber, Barcol hardness and curing shrinkage in percentage. The resultsare shown in Table 1. TABLE 1 Comparative Comparative Example 1 Example2 Example 3 Example 4 Example 5 Example 1 Example 2 Blending Compound ofstructural 60.0 100 (parts by formula (23) mass) Compound of structural60.0 60.0 30.0 40.0 formula (28) Sample A 40.0 Sample B 40.0 Sample C40.0 Sample D 70.0 60.0 CR-39 100 Viscosity (25°) (mPa · s) 144 2160 200180 136 25 10 Initiator IPP (parts by mass) 3 3 3 3 3 3 3 PhysicalRefractive index (n_(D)) 1.525 1.516 1.525 1.518 1.521 1.503 1.517properties Abbe number 53.3 59.7 53.6 57.7 54.9 51.6 56.1 of curedBarcol hardness 25 30 30 13 22 29 47 product Specific gravity 1.2101.198 1.210 1.189 1.194 1.316 1.188 Curing shrinkage in 7.4 9.0 7.3 6.16.2 12.8 11.6 percentage

EXAMPLES 2 TO 5 AND COMPARATIVE EXAMPLES 1 AND 2 Production ofComposition for Plastic Lenses

[0142] Compositions were prepared by the blending shown in Table 1 andmeasured on the viscosity and after the curing, on the refractive index,Abbe number, Barcol hardness and curing shrinkage in percentage, in thesame manner as in Example 1. The results are shown in Table 1.

EXAMPLES 6 TO 10 AND COMPARATIVE EXAMPLES 3 AND 4 Production of PlasticLens

[0143] A vessel containing a solution having each composition shown inTable 1 (compositions of Examples 1 to 5 and Comparative Examples 1 and2) was placed in a desiccator capable of depressurization and thepressure was reduced by a vacuum pump for about 15 minutes to deaerategases in the solution. The resulting solution composition was injectedby a syringe into a mold (thickness: 3 mm) fabricated from a glass-mademold for ophthalmic plastic lenses and a resin-made gasket, while takingcare to prevent intermixing of gas, and then cured in an oven, accordingto a temperature rising program, under heating at 40° C. for 3 hours,heating at from 40 to 85° C. for 3 hours, and heating at 85° C. for 2hours.

[0144] According to the method described above, whether the curedproduct was cracked or not at the curing was observed with an eye. Theresults are shown in Table 2. TABLE 2 Example Comparative ComparativeExample 6 Example 7 Example 8 Example 9 10 Example 3 Example 4 BlendingCompound of structural 60.0 100 (parts formula (23) by mass) Compound ofstructural 60.0 60.0 30.0 40.0 formula (28) Sample A 40.0 Sample B 40.0Sample C 40.0 Sample D 70.0 60.0 CR-39 100 Viscosity (25°) (mpa · s)144   2160    200   180   136    25  10 Initiator IPP (parts by mass) 3 3  3  3  3   3  3 Cracked or not at curing None None None None NoneCracked Cracked

EXAMPLE 11 Production of Plastic Lens

[0145] As shown in Table 3, 95.0 parts by mass of diethylene glycolbisallyl carbonate (CR-39, trade name, produced by PPG), 5.0 parts bymass of Sample A and 3 parts by mass of diisopropylperoxy dicarbonate(IPP) were blended and mixed with stirring to form a completelyhomogeneous solution composition. The viscosity at this time wasmeasured. Thereafter, a vessel containing this solution was placed in adesiccator capable of depressurization and the pressure was reduced by avacuum pump for about 15 minutes to deaerate gases in the solution. Theresulting solution composition was injected by a syringe into a moldfabricated from a glass-made mold for ophthalmic plastic lenses and aresin-made gasket, while taking care to prevent intermixing of gas, andthen cured in an oven, according to a temperature rising program, underheating at 40° C. for 7 hours, heating at from 40 to 60° C. for 10hours, heating at from 60 to 80° C. for 3 hours, heating at 80° C. for 1hour and heating at 85° C. for 2 hours.

[0146] The lens obtained was measured on the refractive index, Abbenumber and Barcol hardness and evaluated on the dyeing speck. Theresults are shown in Table 3.

[0147] In Example 11, the viscosity (at 25° C.) of the compound beforecuring was less than 100 mPa.s.

EXAMPLES 12 TO 15 AND COMPARATIVE EXAMPLE 5 Production of Plastic Lens

[0148] Compositions were prepared by the blending shown in Table 3 andsubjected to measurement on the viscosity and after the curing, on therefractive index, Abbe number and Barcol hardness and to evaluation onthe dyeing speck, in the same manner as in Example 6. The results areshown in Table 3.

[0149] In Examples 12 to 15, the viscosity (25° C.) of each compoundbefore curing was less than 100 mPa.s. TABLE 3 Comparative Example 11Example 12 Example 13 Example 14 Example 15 Example 5 Blending (partsCR-39 95.0 90.0 95.0 95.0 85.0 100 by mass) Sample A 5.0 10.0 Sample B5.0 Sample C 5.0 Sample D 15.0 Initiator IPP (parts by mass) 3 3 3 3 3 3Physical Refractive index (n_(D)) 1.503 1.499 1.501 1.503 1.501 1.499properties Abbe number (ν_(D)) 56.1 60.0 53.6 56.1 64.2 51.6 Barcolhardness 27 23 27 29 25 29 Dyeing failure (number 1 1 1 1 0 8 ofdefectives)

[0150] It is apparent from the results in Tables 1 and 2 that, accordingto the present invention, a plastic lens having high Abbe number andsmall curing shrinkage in percentage can be produced and at the sametime, the curing time can be shortened.

[0151] Furthermore, it is apparent from the result in Table 3 that theplastic lens material of the present invention has an effect ofimproving dyeing of the polyethylene glycol bis(allyl carbonate) resin.

INDUSTRIAL APPLICABILITY

[0152] As verified in the foregoing pages, it is apparent that thecompound of the present invention is a compound having small curingshrinkage in percentage as compared with conventional polyethyleneglycol bis(allyl carbonate) resin and a cured product having high Abbenumber can be produced therefrom similarly to the polyethylene glycolbis(allyl carbonate) resin.

[0153] Accordingly, more efficient production of plastic lenses can beattained than in conventional methods using polyethylene glycolbis(allyl carbonate) resin.

[0154] Furthermore, when the compound of the present invention is usedby mixing it with polyethylene glycol bis(allyl carbonate) resin, dyeingspecks generated in the dyeing of polyethylene glycol bis(allylcarbonate) resin can be improved.

1. A material for plastic lenses, comprising at least one grouprepresented by the following formula (1) as a terminal group and a grouprepresented by the following formula (2) as a repeating unit.

wherein each R¹ independently represents an allyl group or a methallylgroup and each A¹ independently represents an organic residue derivedfrom a dicarboxylic acid or a carboxylic anhydride.

wherein each A² independently represents an organic residue derived froma dicarboxylic acid or a carboxylic anhydride and each X independentlyrepresents an organic residue derived from a polyhydric alcohol havingfrom 2 to 3 hydroxyl groups and containing an alicyclic structure withinthe molecule, provided that by the ester bonding, X can have a branchedstructure having a group of formula (1) as a terminal group and a groupof formula (2) as a repeating unit.
 2. The material as claimed in claim1, wherein the polyhydric alcohol is at least one selected from thecompounds represented by the following structural formulae (7) to (13)and the following formula (14).

wherein each R² independently represents at least one selected from theorganic groups represented by the following structural formulae (15) to(17), each R³ independently represents at least one selected from thefollowing structural formulae (18) to (20), a and b each independentlyrepresents 0 or an integer of 1 to 10, and Y represents any one selectedfrom the organic groups represented by the following structural formulae(21) and (22)).


3. A process for producing a material as set forth in claim 1 or 2,comprising a step of transesterifying at least one selected from thecompounds represented by the following formula (3) with the polyhydricalcohol described in claim 1 or 2 in the presence of a catalyst toobtain a plastic lens material:

wherein A represents an organic residue derived from a dicarboxylic acidor a carboxylic anhydride, and R⁴ and R⁵ each independently representsan allyl group or a methallyl group.
 4. The process as claimed in claim3, wherein the catalyst is at least one member selected from the groupconsisting of tetraisopropoxy titanium, tetrabutoxy titanium, dibutyltinoxide, dioctyltin oxide, hafnium acetylacetonate and zirconiumacetylacetonate.
 5. A composition for plastic lenses, comprising atleast one plastic lens material as set forth in claim 1 or
 2. 6. Acomposition for plastic lenses, comprising from 0.1 to 10 parts by massof at least one radical polymerization initiator per 100 parts by massof a composition for plastic lenses as set forth in claim
 5. 7. Thecomposition for plastic lenses as claimed in claim 6, wherein the atleast one radical polymerization initiator contains diisopropylperoxydicarbonate.
 8. The composition for plastic lenses as claimed in any oneof claims 5 to 7, which has a viscosity at 25° C. of 1,000 mPa.s orless.
 9. A plastic lens obtained by curing a composition for plasticlenses as set forth in any one of claims 5 to
 8. 10. The plastic lens asclaimed in claim 9, wherein a curing shrinkage in percentage at 23° C.is 10.0% or less.
 11. A process for producing a plastic lens as setforth in claim 9 or 10, which comprises curing a plastic lenscomposition as set forth in claim 5 or
 6. 12. The process as claimed inclaim 11, wherein the plastic lens composition is cast polymerized at atemperature of 30 to 120° C. for 0.5 to 100 hours.